Vanadium based olefin polymerization catalyst

ABSTRACT

Catalysts useful in olefin polymerization are a mixture of (a) (i) one or more compounds Zn(X 1 ) 2  and one or more compounds Al(R 1 ) 3 , or (ii) Zn(X 1 ) 2 .2Al(R 1 ) 3 , wherein X 1  is halide and R 1  is C 1-12  hydrocarbyl; and (b) one or more of V(X 2 ) c  (OR 2 ) b-c , VO(X 3 ) d  (OR 3 ) 3-d , or VO(X 4 ) 2 , wherein X 2 , X 3  and X 4  are halogen, R 2  and R 3  are C 1-18  hydrocarbyl, b is 3-4, c is 0-b, and d is 0-3; and can contain (c) one or more of M(R 5 ) e  (X 5 ) 3-e , Al 2  (R 5 ) 3  (X 5 ) 3  or Mg(R 6 ) f  Y 2-f , wherein X 1  and X 2  are halide, R 1 , R 5 , R 6  and R 9  are C 1-  12 hydrocarbyl, M is Al or B, e is 0-3, Y is halide, O--(C 1-12  hydrocarbyl) or N(SiR 9   3 ) 2 , and f is 0-2.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to vanadium-containing polymerizationcatalysts which are especially useful in low temperature, low pressureethylene polymerization processes. The catalyst of the present inventionproduces polymers at a high level of catalyst activity. The catalysts ofthe present invention are designed to provide a high level of responseto hydrogen as a molecular weight control agent. Compositionally, thecatalysts of the present invention comprise compounds of zinc andvanadium. The present invention also relates to the polymerizationprocess utilizing the catalysts and the polymers thus produced.

2. Description of the Prior Art

Vanadium-containing compositions have for some time been proposed foruse in polymerization catalyst systems. Such catalysts, however, havehad relatively little use on a commercial scale since the polymersproduced therewith were produced at a relatively low level of catalystactivity and/or the catalysts produced polymer which had poor morphologyand/or had the tendency to foul the reactor during polymerization.Accordingly, vanadium based catalyst systems have not achievedwidespread use in polymerization--particularly olefin polymerization--ashave titanium or chromium based catalysts. The development ofcommercially useful vanadium-containing polymerization catalysts hasbeen particularly elusive despite the advantages attendant thesesystems, such as easier recovery and better handleability of thecatalyst as well as greater control over the shade and size of thepolymer particle and the overall superior quality of the polymerparticle thus produced.

Examples of the development of supported vanadium based catalyst systemsinclude: U.S. Pat. No. 3,786,032 which describes a catalyst used topolymerize vinyl and vinylidene halides, the catalyst being formed froman inert solid matrix, vanadium compounds and an organo-zinc complexedwith an oxime. U.S. Pat. No. 4,559,318 discloses a vanadium dihalidecomplexed with an ether, such as tetrahydrofuran, and a zinc compound.The catalyst includes a porous support. U.S. Pat. No. 4,611,038describes an olefin polymerization catalyst system prepared from avanadium metal component, a porous support, and an organo-zinc compound;to yield the active solid hydrocarbon catalyst system, a controlledamount of prepolymerization takes place with this composition.

A more recent attempt to produce a high activity vanadium based catalystcomposition which produces high density, high molecular weight alphaolefin polymers that have a relatively broad molecular weightdistribution is described in U.S. Pat. No. 4,866,021. The catalystsystem utilized therein incorporates supported vanadium, aluminum. andzinc compounds and further requires the presence of titanium.

SUMMARY OF THE INVENTION

The present invention is directed to a vanadium-containingpolymerization catalyst. The catalyst is especially useful in lowpressure, low temperature ethylenic and alpha-olefinic polymerizationprocesses, such as ethylene homopolymerization or co-polymerizationwith, for example, 1-hexene.

The catalyst of the present invention also has a high level of responseto hydrogen acting as a molecular weight control agent.

The catalyst of the present invention also produces a polymer,particularly an ethylene polymer, having a broad molecular weightdistribution. The polymer thus produced has good particle morphology andhigh bulk density.

These objects are attained by using a catalyst composition which is theproduct formed by admixing one or more zinc-containing compositions ofthe formula Zn(X¹)₂ with one or more aluminum compositions correspondingto the formula Al(R¹)₃ wherein X¹ is a halide and R¹ is a straight orbranched hydrocarbyl group having from 1 to 12 carbon atoms;

with one or a mixture of vanadium-containing compositions selected fromthe group consisting of compounds having the formula V(X²)_(c)(OR²)_(b-c) where X² is halogen, R² is hydrocarbyl having 1 to about 18carbon atoms, b is the valence of vanadium and is 3 or 4, and c is 0 oran integer from 1 to b; VO(X³)_(d) (OR³)_(3-d) wherein X³ is halogen, R³is hydrocarbyl having 1 to about 18 carbon atoms, and d is 0 or aninteger from 1 to 3; VO(X⁴)₂ wherein X⁴ is halogen: and mixturesthereof.

An additional composition may also be incorporated into the catalyst toenhance or control catalyst activity, the response to hydrogen duringthe polymerization reaction and/or the molecular weight distribution ofthe polymer product.

An additional composition useful in this regard comprises one or amixture of compounds selected from the group consisting of compoundshaving the general formula:

    M(R.sup.5).sub.d (X.sup.5).sub.3-d, Al.sub.2 (R.sup.5).sub.3 (X.sup.5).sub.3,

or

    Mg(R.sup.6).sub.e Y.sub.2-e

wherein M is aluminum or boron; X⁵ is halide; R⁵ is a hydrocarbyl grouphaving from 1 to 12 carbon atoms; d is 0, 1, 2 or 3; R⁶ is a hydrocarbonhaving from 1 to 12 carbon atoms; Y is halide or has the formula OR⁵where R⁸ is C₁ to C₁₂ hydrocarbyl, or Y is a silyl amide having theformula N(SiR⁹ ₃)₂ where R⁹ is C₁ to C₁₂ hydrocarbyl; and e is 0, 1, or2. A description of compounds conforming to this definition of Y isfound in U.S. Pat. No. 4,383,119, the disclosure of which is herebyincorporated herein by reference.

Examples of particular additional compositions include boron alkylhalides--such as ethyl boron dichloride (C₂ H₅ BCl₂)--which function,for example, as molecular weight regulating agents; aluminum halides andaluminum alkyl halides--such as diethyl aluminum chloride ((C₂ H₅)AlCl)or ethyl aluminum dichloride (C₂ H₅ AlCl₂)--which function, for example,to enhance catalyst activity and polymer product properties.

Examples of other additional compositions include magnesium alkylhalides and magnesium alkyls--such as dibutyl magnesium (C₄ H₉)₂ Mg andbutyl ethyl magnesium (C₄ H₉ MgC₂ H₅)--and alkyl magnesium silyl amides,such as butyl magnesium bis trimethyl silyl amide (C₄ H₉MgN(Si(CH₃)₃)₂), all of which function, for example, as molecular weightregulating agents.

In another aspect of the present invention, an olefin polymerizationprocess is disclosed. In this process, olefins such as ethylene and/orone or more alpha-olefins are contacted with the above-identifiedvanadium-containing catalyst, and optionally a modifier, underpolymerization conditions effective to obtain a homopolymer orcopolymer. The olefin polymerization system of the present invention isuseful in gas phase, slurry and solution polymerization processes andfinds particular utility in producing ethylene homopolymers orcopolymers with alpha-olefins, (including polar comonomers, such asvinyl chloride and vinyl alcohol), which polymers have high molecularweight and broad molecular weight distribution.

DETAILED DESCRIPTION OF THE INVENTION

Though not required in the practice of the present invention, ahydrocarbon solvent may be employed as a medium for the preparation ofthe instant catalyst. Non-polar solvents, e.g., alkanes--such as hexaneand heptane, cycloalkanes and aromatics, are preferred. If a solvent isutilized, it is preferred that the solvent is dried in order to removewater. Drying in this regard may be accomplished by storage overmolecular sieves.

In embodiments wherein a solvent is employed, it is preferred that theamount of solvent employed conform to a ratio of about 50 milliliters(mls) of solvent for about every 3 to 5 grams of catalyst. The solventmay be allowed to remain throughout preparation of the catalyst and canbe removed by decantation, filtration or evaporation.

The catalyst of the present invention is the product obtained byadmixing a zinc-containing composition, an aluminum-containingcomposition, and a vanadium-containing composition, as definedhereinbelow. It should be appreciated that no particular sequence ofadmixing is required, and that the present invention contemplatessimultaneous admixing as well as any combination of sequential admixing.Although no particular sequence of admixing need be adhered to, apreferred embodiment of the present invention admixes thezinc-containing and aluminum-containing compositions first, followed bythe vanadium-containing composition, the auxiliary composition, if any,and the modifier, if any.

Admixing preferably occurs at or about room temperature and at or aboutatmospheric pressure; thus no special heating or cooling, and nopressurization or vacuum are necessary, although these may be employedwithout detriment. If other than simultaneous admixing is employed, nospecific time period need elapse between the addition of any one or morecomposition. If sequential admixing is utilized, however, it ispreferred if about 30 minutes elapses between additions.

One preferred method comprises starting with a zinc-aluminum complexcorresponding to the formula

    Zn(X.sup.1).sub.2.2AlR.sup.1.sub.3

wherein X¹ is halogen and R¹ is a straight or branched hydrocarbylhaving from 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms. The R¹is preferably alkyl, cycloalkyl, aryl, aralkyl, or alkaryl and morepreferably is saturated. X¹ is preferably chlorine.

In the practice of the present invention, the zinc-aluminum complex maybe formed by contacting a zinc halide with an aluminum alkyl. Theinvention is not limited to any particular ratio of the zinc-containingand aluminum-containing reactants, it being understood that thosereactants preferentially form the complex at the indicated Zn:Al moleratio of 1:2, with any excess of one or the other reactants remainingpresent. Preferably, the complex is formed by contacting about one moleof zinc chloride with about two moles of triethylaluminum; the formulaof this particular zinc complex is ZnCl₂.2Al(C₂ H₅)₃. Other preferredzinc-aluminum complexes include ZnCl₂.2Al(C₆ H₁₃)₃, and ZnCl₂.2Al(C₄H₉)₃, in the latter the butyl preferably being isobutyl. Thecomplex-forming step preferably occurs separately, before contact withother material which optionally may be employed in forming the catalystcomposition, but can occur upon addition of sufficient quantities of thezinc halide and the aluminum alkyl to slurried admixtures alreadycontaining other components of the catalyst, thus forming thezinc-aluminum complex in situ. The complex thus formed in either case issoluble in non-polar solvents, such as heptane.

The zinc-aluminum complex appears to result in a satisfactorily broadmolecular weight distribution for the polymer, while exhibiting adesired level of activity for the catalyst. The use of the zinc-aluminumcomplex, in any event, is found to be more cost effective in the overallproduction of the catalyst system.

The vanadium-containing compositions useful in the preparation of thecatalyst of the present invention include those which correspond to theformula

    V(X.sup.2).sub.c (OR.sup.2).sub.b-c or VO(X.sup.3).sub.d (OR.sup.3).sub.3-d

where X² and X³ are halogen, preferably chlorine; R² and R³ separatelydenote straight or branched hydrocarbyl having from 1 to about 18 carbonatoms, b is the valence of vanadium and is 3 or 4, and c is zero or aninteger from b and d denotes 0, 1, 2 or 3. Vanadium-containingcompositions useful in the present invention also include those havingthe formula VO(X⁴)₂ wherein X⁴ is halogen, preferably chloride. Mixturesof compounds corresponding to any of these formulas are acceptable. TheR² and R³ groups preferably have 2 to 6 carbon atoms and each is alkyl,aryl, cycloalkyl, aralkyl, or alkaryl, and more preferably is saturated.Examples of preferred compounds represented by these formulas includeVCl₃, VCl₄, VOCl₂, VOCl₃, VO(isopropyl)₃ and one or a mixture of vanadyllower alkoxy (i.e. C₁₋₆) halides such as vanadyl chloride butoxides.

An additional, or auxiliary, composition may, optionally, beincorporated into the admixture to enhance or control polymer and/orcatalytic properties.

Useful auxiliary compositions include those represented by the generalformulas

    M(R.sup.5).sub.e (X.sup.5).sub.3-e

or

    Al.sub.2 (R.sup.5).sub.3 (X.sup.5).sub.3

where M is aluminum or boron, R⁵ represents straight or branchedhydrocarbyl having from 1 to 12 carbon atoms; X⁵ is halogen, preferablychlorine, and e is 0, 1, 2 or 3. Mixtures of compounds corresponding tothe foregoing formulas are also useful. The R⁵ group preferably has 2 to6 carbon atoms and is preferably alkyl, cycloalkyl, aryl, aralkyl, oralkaryl, and more preferably is saturated. Examples of preferredauxiliary compositions having this general formula include diethylaluminum chloride ((C₂ H₅)₂ AlCl), ethyl aluminum dichloride (C₂ H₅AlCl₂) ethyl boron dichloride (C₂ H₅ BCl₂), and boron trichloride(BCl₃).

It should be noted that compounds of the formula Zn(R³)₂ are also usefulauxiliary compositions.

Other auxiliary compositions useful in the reaction product admixtureare magnesium bearing compositions corresponding to the formula

    MgR.sup.6 .sub.f Y.sub.2-f

where R⁶ is hydrocarbyl having from 1 to 12 carbon atoms; Y is halogen,or has the formula OR⁵ where R⁵ is hydrocarbyl containing 1 to 12 carbonatoms, of Y is a silyl amide having the formula N(SiR⁹ ₃)₂ where R⁹ ishydrocarbyl having from 1 to 12 carbon atoms and f is 0, 1 or 2.Preferably, R⁶, R⁶ and R⁹ have 2 to 6 carbon atoms and are alkyl,cycloalkyl, aryl, aralkyl, or alkaryl, and more preferably aresaturated. Y is preferably chlorine. Examples of such suitable auxiliarycompounds include dibutyl magnesium ((C₄ H₉)₂ Mg), butyl ethyl magnesium(C₄ H₉ MgC₂ H₅) and butyl magnesium bis trimethyl silyl amide (C₄ H₉MgN(Si(CH₃)₃)₂ also known as BMSA).

Mixtures of auxiliary compounds may also be used in the practice of theinvention.

The amount of auxiliary composition, when utilized, is about 1:30 toabout 300:1 (mole:mole) based on the amount of vanadium present. Mostpreferably, the amount is between about 1:2 to about 2:1. The auxiliarycomposition may be introduced into the admixture at any point in thesequence of preparation. Thus, for example, the auxiliary compounds maybe introduced before or after the zinc and/or vanadium component. Theauxiliary compounds are, in any event, preferably introduced into theadmixture as a solution in a non-polar hydrocarbon solvent. Alkanes,such as hexane or heptane, are preferred although cycloalkanes andaromatics may also be used. Mixtures of such solvents may also beprovided.

The product obtained by the admixture described herein represents afirst catalyst component which can be combined with a co-catalyst toform an active polymerization catalyst system. A co-catalyst useful inthe practice of this aspect of the present invention includes, e.g., ametal alkyl, metal alkyl hydride, metal alkyl halide, or metal alkylalkoxide, where the metal is aluminum, boron, zinc, or magnesium and thealkyl has 1 to 12 carbon atoms, preferably 2 to 6 carbon atoms. Mixturesof such co-catalysts, may be used with the catalyst composition.Aluminum trialkyls are preferred, with triethylaluminum and/ortri-isobutyl-aluminum especially preferred. Additional examples ofco-catalysts include boron tri(C₁₋₆) alkyls such as B(C₂ H₅)₃, zincdi(C₁₋₆) alkyls such as Zn(C₂ H₅)₂, and magnesium di(C₁₋₆) alkyls suchas C₄ H₉ --Mg--C₂ H₅.

The co-catalyst, when present, is present in an amount that correspondsto a ratio of co-catalyst to vanadium-containing composition of about1:1 to 1000:1, preferably about 5:1 to about 100:1, and more preferablyabout 20:1 to 50:1. The vanadium-containing catalyst and the co-catalystmay be added continuously to the polymerization reactor during thecourse of the polymerization to maintain the desired ratio, orconcentration.

In addition, during the course of polymerization, a modifier for thevanadium based catalyst system may be fed into the reactor. The modifierfunctions to make the vanadium more active. Surprisingly, although thiseffect of increased activity is true for vanadium, the modifier maynevertheless poison other transition metals, if any are present in thecatalyst system of the instant invention.

Modifiers, sometimes referred to as "promoters" in the art, aretypically chosen for their ability to increase and maintain thereactivity of vanadium catalyst, and also affect melt index and meltindex ratio (MIR), which is a measure of molecular weight distribution.

Useful modifiers include halogenating agents such as those of theformula M² H₁ X_(j-i) wherein M² is Si, C, Ge or Sn (preferably Si or C,and most preferably C), X is halogen (preferably Cl or Br and mostpreferably Cl), i is 0, 1, 2 or 3, and j is the valence of M². Suchmodifiers are disclosed in Miro, et al. U.S. Pat. No. 4,866,021 (Sep.12, 1989), the disclosure of which is incorporated herein by reference.Modifiers of this type include chloroform, carbon tetrachloride,methylene chloride, dichlorosilane, trichlorosilane, silicontetrachloride, and halogenated hydrocarbons containing 1 to 6 carbonatoms such as those available from E. I. dupont de Nemours & Co. underthe trade designation Freon (e.g., Freon 11 and Freon 113).

Bachl, et al. U.S. Pat. No. 4,831,090 (May 16, 1989), the disclosure ofwhich is incorporated herein by reference, discloses several classes oforganohalogen compounds which are useful as modifiers. These includesaturated aliphatic halohydrocarbons, olefinically unsaturated aliphatichalohydrocarbons, acetylenically unsaturated aliphatic halohydrocarbons,aromatic halohydrocarbons, and olefinically unsaturated halogenatedcarboxylates.

Particularly preferred modifiers are halocarbon compounds of the formulaR⁶ _(k) CX_(4-k) wherein R⁶ is hydrogen or an unsubstituted or halogensubstituted saturated hydrocarbon having from 1 to 6 carbon atoms; X ishalogen and k is 0, 1 or 2. Examples of these halocarbon compoundsinclude fluoro-, chloro-, or bromo- substituted ethane or methanecompounds having at least two halogens attached to the carbon atom.Especially preferred modifiers include CCl₄, CH_(2l) Cl₂, CBr₄, CH₃CCl₃, CF₂ ClCCl₃, with the most especially preferred being CHCl₃(chloroform), CFCl₃ (Freon 11) and CFCl₂ CCF₂ Cl (Freon 113). Mixturesof any of these modifiers may be used.

Selection of modifiers can be used to adjust polymer properties,sometimes at the expense of activity.

Preferred polymer properties may be obtained with a chosen modifier at aratio of modifier to transition metal which is a compromise to maximumcatalyst activity. The product molecular weight distribution andresponse of melt index to the presence of hydrogen are tunable by choiceand concentration of modifier. Activity, melt index ratio (MIR), highload melt index (HLMI), etc. all vary with the ratio of modifier totransition metal, and with the choice of modifier.

The modifier utilized, when it is utilized, is present in an amount thatcorresponds to a ratio of modifier to vanadium-containing composition of0.1:1 to about 1000:1 (mole:mole), preferably about 1:1 to about 100:1,and more preferably about 5:1 to about 50:1.

After the zinc-containing, aluminum-containing and vanadium-containingcompositions are admixed, with any desired additional components, thecatalyst product thus obtained can be recovered. If a solvent has beenused, the solvent is preferably removed by e.g. decantation, filtrationor evaporation. If evaporation is employed, it is preferred that anitrogen purge at a temperature of about 100° C. be utilized.

It should be appreciated that each step of the preparation of thecatalyst of the present invention is preferably carried out in an inertatmosphere, such as a nitrogen atmosphere. Further, in preparing thecatalyst of the invention, it is desirable that the admixing isconducted under conditions that are substantially free of oxygen. Thusin a preferred embodiment no more than 100 ppm of oxygen, based on theweight of the gaseous atmosphere, is present during catalystpreparation. More preferably, no more than 10 ppm of oxygen is present,and most preferably, no more than 1 ppm of oxygen is present, based onthe weight of the gaseous atmosphere. It is also desirable that theadmixing is conducted under conditions that are substantially free ofwater. Thus in a preferred embodiment, no more than 150 ppm by weight ofwater, based on the weight of the admixture, is present during catalystpreparation. More preferably, no more than 10 ppm by weight of water,and most preferably no more than about 1 ppm by weight of water ispresent, based on the weight of the admixture.

To prepare the catalyst of the present invention, the zinc-containing,aluminum-containing and vanadium-containing compositions are preferablyadmixed after having been formed separately, although they may be formedin situ. The amount of zinc relative to the amount of vanadium is about1:30 to about 300:1 (mole:mole), preferably about 1:17 to about 30:1,and more preferably about 1:2 to about 2:1.

The polymerization reaction may be conducted under solution, slurry orgas phase conditions, at temperatures of about 50° C. up to about 250°C., preferably about 50° C. to about 110° C., and more preferably about65° C. to about 105° C. Suitable pressures are about ambient to 30,000psi, preferably about ambient to about 1000 psi and more preferablyabout ambient to about 700 psi.

The polymer obtained by the process of the present invention may be ahomopolymer of ethylene, a homopolymer of an alpha-olefin, a copolymerof two or more alpha-olefins, or a copolymer of one or morealpha-olefins and ethylene, said alpha-olefins, as this term is used inthis specification, having 3 to 12 carbon atoms. Alpha-olefinsparticularly useful in the present invention include propylene,1-butene, 1-pentene, 1-hexene, 1-octene, 1,3-butadiene and1,5-hexadiene.

The operator may in accordance with known techniques feed controlledamounts of H₂ into the reaction at the beginning of the polymerization,during it, or both, to control or modify the molecular weight of thepolymer product.

The polymer thus produced can have a melt index (MI) at 190° C. and 2.16kg (as measured by ASTM D1238-82) as high as up to about 1000, includinga melt index as low as about 0.01 or less. The melt index ratios(HLMI/MI) of the polymer capable of being produced will vary dependingon the above parameters of HLMI and MI; for example, the HLMI/MI can bebetween about 25 and about 150. The melt-index ratio correlates tomolecular weight distribution (MWD). The term "HLMI" as used hereinmeans the high load melt index as measured at 190° C. and 21.6 kg inaccordance with ASTM D1238-82.

With either of the cocatalyst and modifier ratios, however, departurefrom the preferred values results in diminished activity and changes inpolymer properties, i.e., MI and MIR. How these properties changediffers with different catalyst components of the invention. Polymerproperties may be tuned by varying cocatalyst and modifier levels,sometimes with a compromise of activity in order achieve desiredproperties.

The catalysts of the present invention are also notable in that theirutilization does not require the presence of a support material, such assilica or other customary catalyst supports.

The catalysts of the present invention are also advantageous in thatthey provide to the user the ability tailor the properties of thepolymer that is desired. The vanadium present affords sensitivity to thepresence of hydrogen added to control of the molecular weight of thepolymer. Higher polymer molecular weights are associated with higherstrength, whereas lower molecular weights tend to be associated withgreater processability. The catalyst of this invention allows one toachieve essentially any desired balance of strength and processability.

The polymers produced by the catalysts of the present invention do notrequire polymer de-ashing to be commercially acceptable in low ashpolymer applications.

The catalyst systems of the present invention may be readily used undersolution, slurry, or gas phase polymerization conditions.

The following examples are merely illustrative of the scope of thepresent invention and are not intended as a limitation therein.

EXAMPLE 1

This example demonstrates the preparation of a complex corresponding tothe formula ZnCl₂.2Al(CH₂ CH₃)₃. To a dry, empty Fisher-Porter bottle ina dry box were added 46.96 grams of ZnCl₂ followed by 440 ml of a 1.56molar solution of triethyl aluminum which was added through a cannula.The bottle was heated to 90° C. for 1 hour and then allowed to cool toroom temperature. Inspection two days later revealed a clear solutionwith a dark precipitate at the bottom, which was recovered byfiltration. The complex was used without any further purification. Thesolution was understood to have a zinc concentration of about 0.34 molarand an aluminum concentration of about 0.69 molar. The concentration ofthe ZnCl₂.2Al(CH₂ CH₃)₃ complex was assumed to be 0.34 molar.

EXAMPLE 2

A mixture of vanadium compounds was prepared by the following chemicalreaction: VOCl₃ +1.5 (C₄ H₉ OH)=VO(OC₄ H₉)₂ Cl+VO(OC₄ H₉)Cl₂ +VO(OC₄H₉)₃ +HCl.

This example demonstrates the preparation of the vanadium compounds.

9.42 ml of VOCl₃ (density 1.84 g/ml) was stirred together with 13.73 mlof butyl alcohol (density 0.810 g/ml. Then, 76.9 ml of heptane was addedto make up a 1 molar solution corresponding to the stoichiometricrepresentation VOCl₁.5 (OC₄ H₉)₁.5. The solution was sparged with lowflow N₂ for 5 minute to remove any HCl gas produced by theabove-depicted reaction.

EXAMPLE 3

This example demonstrates the preparation of a catalyst composition ofthe present invention.

To a dry, empty 3-neck flask equipped with a magnetic stirring bar wasadded 15 ml (15 mM in V) of a solution prepared in accordance withExample 2 and 50 ml of heptane. The contents were held at 70° C. Then38.5 ml (13.1 mM in Zn and Al) of a solution of a complex of ZnCl₂.Al(C₂H₅)₃ prepared in accordance with Example 1, which had been heated to 70°C., was added dropwise over a 1-hour period with stirring of thecontents of the flask. Heat and smoke were generated by the addition. Aslurry formed which, at the end of the addition of the zinc complex, waswashed three times with 150 ml of heptane, decanted, filtered and dried.

EXAMPLE 4

All preparations of the catalysts and chemicals described herein toprepare the catalysts were carried out under a nitrogen atmosphere.Typically a 3 neck round bottom flask fitted with a paddle type stirrerwas used for the catalyst preparations. Some of the chemical reactionsto prepare the chemical precursors were prepared in Fisher Porterbottles.

Catalyst Run A:

To the round bottom flask was added 15 ml of the 1.0M solution of theVanadium compounds whose preparation was described in Example 2.

Next 50 mls of heptane were added.

With good stirring the following was added dropwise to the flask: 38.5mls of a 0.34M solution of the [Zn-Al] complex whose preparation wasdescribed in Example 1. The flask was then stirred for about 60 min. atambient temperature and then filtered and washed 3 times with 150 mlseach time of heptane. The catalyst was isolated by vacuum drying.

Catalyst Run B:

Using equipment equivalent to that described above, and

    ______________________________________                                        VOCl.sub.3 1.0M,      10     mls                                              Heptane               50     mls                                              Zn--Al complex        25.6   mls                                              VO(OiPr).sub.3 1.0M,  10     mls                                              ______________________________________                                    

The 25.6 mls of the solution of Zn--Al complex whose preparation wasdescribed in Example 1 was added dropwise to a solution of 1 mole ofVOCl₃ in 60 ml of heptane, while the flask was kept cool in a beaker ofwater at -20° C. A precipitate formed; the reaction mixture was stirred60 minutes at ambient temperature. Next 10 mls of 1.0M VO(OiPr)₃solution was added slowly (iPr=isopropyl). The product was stirred 30minutes at ambient temperature. The solid was allowed to settle and wasfiltered. The catalyst was washed 3 times with 150 mls each time ofheptane. The catalyst was filtered and dried under vacuum.

Catalyst Run C:

To the 3 neck round-bottom flask fitted with a mechanical stirrer wasadded in the following order:

ZnCl₂.2AlEt₃, 12.9 ml (10 mM);

Heptane, 50 ml;

VO(OiPr)₃ 1M, 10 ml (10 mM);

ZnEt₂ 1.0M, 10 ml;

VOCl₃ 1M, 10 ml

The vanadium solution was added dropwise to form a brown precipitate.This mixture was stirred for 30 min at ambient conditions, then 10 ml ofZnEt₂ (1M=10 mM) was added followed by 10 ml of 1.0M VOCl₃ solution(dropwise).

The catalyst was stirred 30 min at ambient temperature then allowed tosettle. The catalyst was filtered and washed three time with 150 mlseach time of heptane. The final catalyst was obtained by vacuum drying.

EXAMPLE 5

The catalysts of Runs A, B and C in Example 4, prepared as describedabove, were each used to homopolymerize ethylene under slurrypolymerization conditions in a slurry polymerization reactor. Each ofthe polymerization reactions was conducted in 600 milliliters ofisobutane at a temperature of about 93.3° C. or 80° C. and a totalpressure adjusted to yield the ethylene concentrations noted in thefollowing tables. The reactions were each conducted for about 60minutes. Ethylene concentration in isobutane was about 4-20 mole percentand was maintained at this level at all times of the polymerizationreaction by the constant feeding of ethylene into the reactor. About 40milligrams of catalyst was used in each polymerization example.

The catalyst and a catalyst modifier (chloroform, Freon 113) wereinjected into the reactor at full reactor pressure, that is, pressurefrom H₂, isobutane and ethylene. About 0.5 milliliters of an aluminumalkyl cocatalyst (triethyl aluminum or triisobutyl aluminum) wassyringed into the reactor for each experiment as a 25 weight percentsolution thereof in heptane. The mole ratio of hydrogen to ethylene (C⁼₂) used in the experiments was either 0.077:1 or 0.155:1. The mole ratioof modifier (CHCl₃), when used, to vanadium-containing composition##EQU1## was either 20:1 or 50:1. The mole ratio of cocatalyst tovanadium-containing composition ##EQU2## ranged from 5:1 to 25:1,respectively.

Tables 1-3, below, show the mole ratios of the various materials thatwere used and the results that were obtained therewith in terms ofcatalyst reactivity (grams polyethylene/grams of total catalyst per hourof reaction time), the melt index (MI), and melt index ratio (MIR=HLMI/MI) of the polymer products relative to the particular catalystsystem used.

Hydrogen was added to the reactor from a vessel of known volume (about150 ml); the amount of hydrogen added was measured as ΔP, the change(decrease) in the hydrogen pressure in that vessel, measured in psi.

                  TABLE 1                                                         ______________________________________                                        Catalyst from Example 4, Run A                                                Test Temp.   Mole %   H.sub.2                                                                            Modi-   React-                                     No.  °C.                                                                            C.sub.2 H.sub.4                                                                        (ΔP)                                                                         fier    ivity MI   MIR                             ______________________________________                                        1    93.3    7        40   None    2,200 1.33 52.                             2    80.     10       25   CHCl.sub.3                                                                            15,800                                                                              0.12 78.                             3    93.3    4        25   CHCl.sub.3                                                                            9,400 0.23 74.                             4    93.3    4        25   Freon 113                                                                             6,000 0.46 66.                             ______________________________________                                    

Test No. 1 demonstrates that the catalyst in accordance with the presentinvention exhibits good reactivity even without the use of a modifier.The polymer product had a narrower molecular weight distribution thanthat obtained in Tests 2-4.

Test No. 2 demonstrates that the catalyst in accordance with the presentinvention exhibits very high reactivity when used with CHCl₃ as amodifier.

Test No. 3 demonstrates that the catalyst of the present inventionexhibits very high activity even at very low ethylene concentrations.

Test No. 4 demonstrates that the catalyst of the present inventionexhibits good activity using a different modifier (Freon 113, which isCF₂ ClCCl₂ F).

Tests 1-4 show that the present invention affords the operator theability to tailor the molecular weight distribution to desired valuesvia straightforward adjustments of conditions and feed materials.

                  TABLE 2                                                         ______________________________________                                        Catalyst from Example 4, Run B                                                Test Temp.   Mole %   H.sub.2                                                                            Modi-   React-                                     No.  °C.                                                                            C.sub.2 H.sub.4                                                                        (ΔP)                                                                         fier    ivity MI   MIR                             ______________________________________                                        5    93.3    4        40   CHCl.sub.3                                                                             3,400                                                                              5.10 68.                                                        premixed                                                                      w/TIBAL                                            6    93.3    7        75   CHCl.sub.3                                                                            11,430                                                                              2.63 68.                             ______________________________________                                    

Tests 5 and 6 demonstrate that preparing the catalyst of the presentinvention with two distinct vanadium-containing feed materials stillprovided catalyst exhibiting very good activity that produced polymersof medium to broad molecular weight distribution (as evidenced by theMIR values).

                  TABLE 3                                                         ______________________________________                                        Catalyst from Example 4, Run C                                                Test Temp.   Mole %   H.sub.2                                                                            Modi-   React-                                     No.  °C.                                                                            C.sub.2 H.sub.4                                                                        (ΔP)                                                                         fier    ivity MI   MIR                             ______________________________________                                        7    93.3    4        40   CHCl.sub.3                                                                            4,880 0.81 73.                             8    93.3    4        40   Freon 113                                                                             2,330 0.92 60.                             9    80.     10       40   CHCl.sub.3                                                                            5,400 2.71 62.                             ______________________________________                                    

Tests 7-9 demonstrated catalysts according to the present inventionhaving high reactivity. Comparison of Tests 1-9 demonstrates the abilityto adjust the MI higher or lower, as desired, as well as broader ornarrower molecular weight distribution (as measured by the MIR), withreaction conditions including the choice of modifier. The catalysts ofthe present invention surprisingly exhibit desirably high reactivityeven at higher hydrogen concentrations.

What is claimed is:
 1. An unsupported catalyst consisting essentially ofthe product produced by admixing:(a) (i) one or more zinc-containingcompositions corresponding to the formula Zn(X¹)₂ and one or morealuminum-containing compositions corresponding to the formula Al(R¹)₃ ;or (ii) a composition of the formula Zn(X¹)₂.2Al(R¹)₃ ; wherein X¹ is ahalide, and wherein R¹ is a hydrocarbyl group having from 1 to about 12carbon atoms; and (b) a vanadium composition selected from the groupconsisting of compounds having the formula V(X²)_(c) (OR²)_(b-c) whereinX² is halogen, R² is hydrocarbyl having 1 to about 18 carbon atoms, b isthe valence of vanadium and is 3 or 4 and c is 0 or an integer from 1 tob; VO(X³)_(d) (OR³)_(3-d) wherein X³ is halogen, R³ is hydrocarbylhaving 1 to about 18 carbon atoms, and d is 0 or an integer from 1 to 3;VO(X⁴)₂ wherein X⁴ is halogen and mixtures thereof.
 2. An unsupportedcatalyst consisting essentially of the product produced by admixing:(a)(i) one or more zinc-containing compositions corresponding to theformula Zn(X¹)₂ and one or more aluminum-containing compositionscorresponding to the formula Al(R₁)₃ ; or (ii) a composition of theformula Zn(X¹)₂.2Al(R¹)₃ ; wherein X¹ is a halide, and wherein R¹ is ahydrocarbyl group having from 1 to about 12 carbon atoms; (b) a vanadiumcomposition selected from the group consisting of compounds having theformula V(X²)_(c) (OR²)_(b-c) wherein X² is halogen, R² is hydrocarbylhaving 1 to about 18 carbon atoms, b is the valence of vanadium and is 3or 4 and c is 0 or an integer from 1 to 3; VO(X³)_(d) (OR₃)_(3-d) whereX³ is halogen, R³ is hydrocarbyl having 1 to about 18 carbon atoms, andd is 0 or an integer from 1 to 3; VO(X⁴)₂ wherein X⁴ is halogen, andmixtures thereof; and (c) one or more additional compositions selectedfrom the group consisting of compounds having the formula

    M(R.sup.5).sub.e X.sup.5.sub.3-e or Al.sub.2 (R.sup.5).sub.3 X.sup.5.sub.3

wherein M is Al or B, X⁵ is a halide, R⁵ is a hydrocarbyl group havingfrom 1 to about 12 carbon atoms, and e is 0, 1, 2 or 3; and compoundshaving the formula

    Mg(R.sup.6).sub.f Y.sub.2-f

wherein R⁶ is a hydrocarbyl group having from 1 to about 12 carbonatoms, Y is a halide or has the formula OR⁸ where R⁸ is hydrocarbylhaving from 1 to about 12 carbon atoms, or Y is a silyl amide having theformula --N(SiR⁹ ₃)₂ wherein R⁹ is hydrocarbyl having from 1 to about 12carbon atoms, and f is 0, 1 or
 2. 3. The catalyst of claim 1 wherein R¹is alkyl, cycloalkyl, aryl, aralkyl, alkaryl or mixtures thereof.
 4. Thecatalyst of claim 3 wherein R¹ is alkyl having 1 to 6 carbon atoms. 5.The catalyst of claim 4 wherein R¹ is --C₂ H₅.
 6. The catalyst of claim5 wherein X¹ is chloride.
 7. The catalyst of claim 6 wherein saidvanadium-containing composition is selected from the group consisting ofVCl₃, VCl₄, VOCl₂, VOCl₃, VO(iOC₃ H₇)₃ and mixtures thereof.
 8. Thecatalyst of claim 1 wherein X¹ is chloride.
 9. The catalyst of claim 1wherein R² and R³ are selected from the group consisting of alkyl,cycloalkyl, aryl, aralkyl and alkaryl.
 10. The catalyst of claim 9wherein R² and R³ are alkyl having 1 to 6 carbon atoms.
 11. The catalystof claim 10 wherein X², X³ and X⁴ are chloride.
 12. The catalyst ofclaim 1 wherein X.sup. 2, X³ and X⁴ are chloride.
 13. The catalyst ofclaim 1 wherein said vanadium-containing composition is selected fromthe group consisting of VCl₃, VCl₄, VOCl₂, VOCl₃, VO(iOC₃ H₇)₃ andmixtures thereof.
 14. The catalyst of claim 2 wherein R⁵, R⁶, R⁸ and R⁹are alkyl, cycloalkyl, aryl, aralkyl or alkaryl.
 15. The catalyst ofclaim 14 wherein R⁵, R⁶, R⁸ and R⁹ are alkyl having 1 to 6 carbon atoms.16. The catalyst of claim 2 wherein X⁵ is chloride.
 17. The catalyst ofclaim 2 wherein said additional composition is selected from the groupconsisting of (C₂ H₅)₂ AlCl, C₂ H₅ AlCl₂, (C₂ H₅)₃ Al₂ Cl₃, (C₄ H₉)₂ Mg,Zn(C₂ H₅)₂, C₄ H₉ H₅ Mg, C₂ H₅ BCl₂, BCl₃, C₄ H₉ MgN(Si(CH₃)₃)₂ andmixtures thereof.
 18. The catalyst of claim 1 wherein said product issubstantially free of titanium.
 19. An unsupported olefin polymerizationcatalyst system consisting ofA. a catalyst consisting essentially of theproduct produced by admixing: (a) (i) one or more zinc-containingcompositions corresponding to the formula Zn(X¹)₂ and one or morealuminum-containing compositions corresponding to the formula Al(R¹)₃ ;or (ii) a composition of the formula Zn(X¹)₂.2Al(R¹)₃ ; wherein X¹ is ahalide, and wherein R¹ is a hydrocarbyl group having from 1 to about 12carbon atoms, and (b) a vanadium composition selected from the groupconsisting of compounds having the formula V(X²)_(c) (OR²)_(b-c) whereinX² is halogen, R² is hydrocarbyl having 1 to about 18 carbon atoms, b isthe valence of vanadium and is 3 or 4 and c is 0 or an integer from 1 to3; VO(X³)_(d) (OR³)_(3-d) wherein X³ is halogen, R³ is hydrocarbylhaving 1 to about 18 carbon atoms, and d is 0 or an integer from 1 to 3;VO(X⁴)₂ wherein X⁴ is halogen, and mixtures thereof; and B. aco-catalyst wherein the co-catalyst is a metal alkyl, metal alkylhydride, metal alkyl halide, or metal alkyl alkoxide.
 20. The olefinpolymerization catalyst system claim 19 wherein the metal is aluminum,boron, zinc, or magnesium.
 21. The olefin polymerization catalyst systemclaim 19 wherein the alkyl has 1 to 12 carbon atoms.
 22. The olefinpolymerization catalyst system of claim 19 wherein the alkyl has 2 to 6carbon atoms.
 23. The olefin polymerization catalyst system claim 19wherein the co-catalyst is triethyl alumina, triisobutyl aluminum, or amixture thereof.
 24. The olefin polymerization catalyst system claim 19wherein the ratio of metal in the co-catalyst to vanadium in thecatalyst is about 1:1 to about 1000:1.
 25. An unsupported polymerizationcatalyst system consisting essentially ofA. a catalyst consistingessentially of the product produced by admixing: (a) (i) one or morezinc-containing compositions corresponding to the formula Zn(X¹)₂ andone or more aluminum-containing compositions corresponding to theformula Al(R¹)₃ ; or (ii) a composition of the formula Zn(X¹)₂ Al(R¹)₃ ;wherein X¹ is a halide, and wherein R¹ is a hydrocarbyl group havingfrom 1 to about 12 carbon atoms; and (b) a vanadium composition selectedfrom the group consisting of compounds having the formula V(X²)_(c)(OR²)_(b-c) wherein X² is halogen, R² is hydrocarbyl having 1 to about18 carbon atoms, b is the valence of vanadium and is 3 or 4 and c is 0or an integer from 1 to b; VO(X³)_(d) (OR³)_(3-d) wherein X³ is halogen,R³ is hydrocarbyl having 1 to about 18 carbon atoms, and d is 0 or aninteger from 1 to 3; VO(X⁴)₂ wherein X⁴ is halogen, and mixturesthereof; and B. a co-catalyst wherein the co-catalyst is a metal alkyl,metal alkyl hydride, metal alkyl halide, or metal alkyl alkoxide; and C.a modifier wherein the modifier corresponds to the formula

    M.sup.2 H.sub.i X.sub.j-1

wherein M² is Si, C, Ge or Sn, X is halogen, i is 0, 1, 2 or 3, and j isthe valence of M².
 26. The olefin polymerization catalyst system ofclaim 25 wherein said modifier corresponds to the formula R⁶ _(k)CX_(4-k) wherein R⁶ is hydrogen or an unsubstituted or halogensubstituted hydrocarbon having 1 to 6 carbon atoms; X is halogen; and kis 0, 1 or
 2. 27. The olefin polymerization catalyst system claim 25wherein the modifier is CCl₄, CH₂ Cl₂, CBr₄, CH₃ CCl₃, CF₂ ClCCl₃,CHCl₃, CFCl₃, CFCl₂ CF₂ Cl, or mixtures thereof.
 28. An unsupportedolefin polymerization catalyst system consisting essentially ofA. acatalyst comprising the product produced by admixing: (a) (i) one ormore zinc-containing compositions corresponding to the formula Zn(X¹)₂and one or more aluminum-containing compositions corresponding to theformula Al(R₁)₃ ; or (ii) a composition of the formula Zn(X¹)₂.2Al(R¹)₃; wherein X¹ is a halide, and wherein R¹ is a hydrocarbyl group havingfrom 1 to about 12 carbon atoms; (b) a vanadium composition selectedfrom the group consisting of compounds having the formula V(X²)_(c)(OR²)_(b-c) wherein X² is halogen, R² is hydrocarbyl having 1 to about18 carbon atoms, b is the valence of vanadium and is 3 or 4 and c is 0or an integer from 1 to b; VO(X³)_(d) (OR₃)_(3-d) where X³ is halogen,R³ is hydrocarbyl having 1 to about 18 carbon atoms, and d is 0 or aninteger from 1 to 3; VO(X⁴)₂ wherein X⁴ is halogen, and mixturesthereof; and (c) one or more additional compositions selected from thegroup consisting of compounds having the formula

    M(R.sup.5).sub.e X.sup.5.sub.3-e or Al.sub.2 (R.sup.5).sub.3 X.sup.5.sub.3

wherein M is Al or B, X⁵ is a halide, R⁵ is a hydrocarbyl group havingfrom 1 to about 12 carbon atoms, and e is 0, 1, 2 or 3; and compoundshaving the formula

    Mg(R.sup.6).sub.f Y.sub.2-f

wherein R⁶ is a hydrocarbyl group having from 1 to about 12 carbonatoms, Y is a halide or has the formula OR⁸ where R⁸ is hydrocarbylhaving from 1 to about 12 carbon atoms, or Y is a silyl amide having theformula --N(SiR⁹ ₃) wherein R⁹ is hydrocarbyl having from 1 to about 12carbon atoms, and f is 0, 1 or 2; and B. a co-catalyst wherein theco-catalyst is a metal alkyl, metal alkyl hydride, metal alkyl halide,or metal alkyl alkoxide.
 29. An unsupported olefin polymerizationcatalyst system consisting essentially ofA. a catalyst comprising theproduct produced by admixing: (a) (i) one or more zinc-containingcompositions corresponding to the formula Zn(X¹)₂ and one or morealuminum-containing compositions corresponding to the formula Al(R₁)₃ ;(ii) a composition of the formula Zn(X¹)₂.2Al(R¹)₃ ; wherein X¹ is ahalide, and wherein R¹ is a hydrocarbyl group having from 1 to about 12carbon atoms; (b) a vanadium composition selected from the groupconsisting of compounds having the formula V(X²)_(c) (OR²)_(b-c) whereinX² is halogen, R² is hydrocarbyl having 1 to about 18 carbon atoms, b isthe valence of vanadium and is 3 or 4 and c is 0 or an integer from 1 tob; VO(X³)_(d) (OR₃)_(3-d) where X³ is halogen, R³ is hydrocarbyl having1 to about 18 carbon atoms, and d is 0 or an integer from 1 to 3;VO(X⁴)₂ wherein X⁴ is halogen, and mixtures thereof; and (c) one or moreadditional compositions selected from the group consisting of compoundshaving the formula

    M(R.sup.5).sub.e X.sup.5.sub.3-e or Al.sub.2 (R.sup.5).sub.3 X.sup.5.sub.3

wherein M is Al or B, X⁵ is a halide, R⁵ is a hydrocarbyl group havingfrom 1 to about 12 carbon atoms, and e is 0, 1, 2 or 3; and compoundshaving the formula

    Mg(R.sup.6).sub.f Y.sub.2-f

wherein R⁶ is a hydrocarbyl group having from 1 to about 12 carbonatoms, Y is a halide or has the formula OR⁸ where R⁸ is hydrocarbylhaving from 1 to about 12 carbon atoms, or Y is a silyl amide having theformula --N(SiR⁹ ₃)₂ wherein R⁹ is hydrocarbyl having from 1 to about 12carbon atoms, and f is 0, 1 or 2; B. a co-catalyst wherein theco-catalyst is a metal alkyl, metal alkyl hydride, metal alkyl halide,or metal alkyl alkoxide; and C. a modifier wherein the modifiercorresponds to the formula

    M.sup.2 H.sub.i X.sub.j-i

wherein M² is Si, C, Ge or Sn, X is halogen, i is 0, 1, 2 or 3, and j isthe valence of M².